1. Field of the Invention
The present invention relates to a storage medium having a game program stored therein and a game apparatus and game processing method therefor. More specifically, the present invention relates to a storage medium having stored therein a game program for arranging a plurality of objects in a virtual game world and a game apparatus and game processing method therefor.
2. Description of the Background Art
Conventionally, an image closely representing a real world has been obtained by generating a game image in which a plurality of game objects are arranged in a virtual game world. When the real world in which a plurality of objects are randomly arranged is to be represented in a virtual world, a plurality of game objects representing the plurality of objects of the real world have to be arranged in random positions in order to make the virtual world seem real.
Japanese Laid-Open Patent Publication No. 10-31410 (herein after, referred to as “patent document 1”) discloses an apparatus in which falling matters such as snow are represented in a virtual three dimensional space, for example. In the apparatus disclosed in patent document 1, a plurality of falling objects which are arranged in the three dimensional space are used to represent a plurality of real falling matters. The objects are then made to move downwardly while they are rotated in a predetermined rotation direction and by a predetermined rotation angle, so that a state of falling of a falling matter arranged in a respective falling object is depicted. Note that, in representing falling matters such as snow by using falling objects, types of falling matters used and their spatial arrangements may be made same for all falling objects so as to reduce a processing load, or spatial arrangements for the falling objects may be made different from each other.
However, in the real world, the distance between a plurality of matters randomly arranged differs depending on the likelihood of the matters to overlap each other or the like. In representing a real matter in a virtual game world, simply arranging a game object representing the matter in a random manner cannot yield a natural representation therefor. The likelihood of the matter to overlap with another has to be considered. For example, positions of a plurality of matters (e.g., fallen leaves around a deciduous tree) within a predetermined area of the ground in the real world are random and the matters frequently overlap each other. On the other hand, positions of a plurality of matters (e.g., floating weeds growing in crowds) which float within a predetermined area of a water surface are random but the matters less frequently overlap each other.
In the case of representing such a plurality of matters in a virtual game world, if a plurality of game objects representing the former type are randomly arranged in the virtual world but not in an overlapping manner, a player's experience feels unnatural. On the other hand, if a plurality of game objects representing the latter type are randomly arranged in the virtual world but in an overlapping manner, the player's experience feels unnatural. Also, for both of the former and latter types, if a plurality of game objects are arranged in fixed positions for which the likelihoods of the objects to overlap each other are considered, the player constantly views the game objects having a same arrangement relationship and therefore, the player's experience feels unnatural since the matters in reality exist in a random manner. In other words, by simply arranging game objects in a random manner without considering the likelihood of represented matters to overlap each other or arranging game objects in fixed positions with a consideration of the likelihood of represented matters to overlap each other, the player's experience feels unnatural in some cases.